The metabolic activity of cells from the various layers of the cornea and the possible in vitro regulatory mechanism between the layers were investigated: 1. A microculture for accurate and reproducible information concerning the rate of DNA of protein synthesis at a cellular level has been developed. 2. Organ cultures of endothelium with its Descemet's membrane were used as a model for the study of endothelial wound repair mechanism in vitro. The possibility of transplantation of these organ cultures was also evaluated. 3. Combined organ cultures: The effects of the various layers of the cornea on each other were studied in mixed organ cultures. A possible interaction and/or regulation between epithelium and stroma has been observed. Studies are underway in order to detect any possible interactions in stroma-endothelium or endothelium-epithelium organ cultures.